Microcirculatory rarefaction in South Asians - a potential mechanism for increased cardiovascular risk and diabetes.
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ABSTRACT: People of South Asian descent have an increased risk of cardiovascular disease (CVD) and diabetes, but little is known about the microcirculation in South Asian people despite evidence that this plays an important role in the aetiology of CVD. We compared the retinal microcirculation in a population-based sample of 287 middle-aged adults (144 European 143 South Asian) matched for age and sex. Retinal photographs were taken and analysed using a validated semi-automated program and microvascular measures were compared. Blood pressure, anthropometry and fasting bloods were also measured. South Asians had significantly fewer arteriolar and venular vessels and bifurcations. Arterioles and venules were longer and venules were also more tortuous in South Asians. These differences were not explained by adjustment for traditional risk factors including blood pressure, body mass index, diabetes or measures of insulin resistance. People of South Asian descent have rarefaction of the retinal microcirculation compared to age-sex matched individuals of European descent. Reduced microvascular density could contribute to the elevated risk of CVD and impaired glucose tolerance in South Asian people.
Project description:BackgroundSouth Asians represent about 3% of the Canadian population and have a higher burden of certain cardiovascular risk factors and cardiovascular disease (CVD) compared with white people. The objective of this study was to review the literature to compare cardiovascular risk factors and disease management practices among adult South Asian and white Canadians.MethodsWe searched MEDLINE, Embase, Cochrane and Cumulative Index to Nursing and Allied Health Literature databases from their inception through Feb. 17, 2014 and the reference lists of the selected articles. English-language studies of interventions and observational studies of biological mechanisms underlying CVD risk in South Asians conducted in Canada were eligible for inclusion. Where appropriate, we used random-effects meta-analyses to integrate results comparing the CVD risk profiles of South Asian and white Canadians.ResultsWe included 50 articles (n = 5 805 313 individuals) in this review. Compared with white Canadians, South Asian Canadians had a higher prevalence and incidence of CVD, an increased prevalence of diabetes (odds ratio [OR] 2.25, 95% confidence interval [CI] 1.81 to 2.80, p < 0.001) and hypertension (OR 1.11, 95% CI 1.02 to 1.22, p = 0.02), lower high-density lipoprotein cholesterol levels (mean difference -0.19 mmol/L, 95% CI -0.25 to -0.13 mmol/L, p < 0.001) and a higher percentage of body fat (men: absolute mean difference 3.23%, 95% CI 0.83% to 5.62%, p = 0.008; women: absolute mean difference 4.09%, 95% CI 3.46% to 4.72%, p < 0.001). South Asian people are also more sedentary, consume higher levels of carbohydrates and are less likely to smoke tobacco (OR 0.38, 95% CI 0.24 to 0.60, p < 0.001]) than white Canadians. No differences in access to diagnostic tests, outcomes following cardiovascular surgery or use of cardiac rehabilitation programs were apparent.InterpretationCompared with white people, South Asian people living in Canada have a higher prevalence and incidence of CVD and possess a unique cardiovascular risk profile.
Project description:Objective:We evaluated the effects of a diabetes prevention itervention on self-efficacy (SE) and the associations between SE and diabetes-related outcomes among overweight Asian Indian adults with pre-diabetes in a randomized controlled translational trial (the Diabetes Community Lifestyle Improvement Program, D-CLIP). Research design and methods:Data were obtained from 550 adults who were randomized to a diabetes prevention program or standard of care. Dietary and exercise-related SEs were measured at baseline, core intervention completion (4 ?months), and annually until the end of follow-up (3 years or diabetes diagnosis). Mixed-effects regressions described changes in SE over time by treatment group. Among treatment participants, multivariable-adjusted models described associations of SE at baseline and intervention completion with diabetes incidence and other secondary outcomes (weight, waist circumference (WC), exercise, and energy intake). Results:From baseline to 4 ?months, dietary (?=10.3, p=0.04) and exercise (?=0.49, p=0.04) SE increased significantly in the treatment arm only; however, this increase from baseline was no longer significant at later time points. Among treatment participants, there was no association of dietary or exercise SE with diabetes incidence, but baseline exercise SE was independently associated with improved weight, WC, and exercise at 4 ?months (p<0.05). Change in exercise SE from baseline to intervention completion also predicted increased exercise at 4, 12, and 24 months (p<0.05). Conclusions:Exposure to D-CLIP resulted in improved SE at treatment completion, but this effect was not sustained over longer follow-up. Several short-term and long-term secondary outcomes, but not diabetes risk, were significantly associated with exercise SE, suggesting this psychosocial trait may facilitate success in achieving certain health goals. Trial registration number:NCT01283308.
Project description:BackgroundThe cardiovascular disease (CVD) burden among South Asians is high. Lifestyle interventions have been effective in the primary prevention of CVD, but this has not been replicated, through a synthesis of randomised trials, in South Asians.MethodsFour electronic databases (MEDLINE, Embase, CENTRAL and CINAHL), two clinical trial registries and references of included articles were searched through June 2022 (featuring ≥90% South Asian participants). Random-effects pairwise meta-analyses were performed, and heterogeneity was quantified with the I2 statistic. The Grades of Recommendation, Assessment, Development, and Evaluation (GRADE) framework was used to report on the quality of evidence (International Prospective Register of Systematic Reviews registration (PROSPERO).ResultsThirty-five studies were included. Twelve tested diet and physical activity interventions; 18 tested diet alone; and 5 tested physical activity alone. All reported effects of the intervention(s) on at least one established risk factor for CVD, including blood pressure (systolic blood pressure (SBP), diastolic blood pressure (DBP) and blood lipids (high-density lipoprotein cholesterol (HDLc), low-density lipoprotein cholesterol (LDLc) or triglycerides). No trials reported clinical CVD. There is moderate-quality evidence that diet and physical activity interventions improve SBP (mean difference (MD) -2.72 mm Hg, 95% CI -4.11 to -1.33) and DBP (MD -1.53 mm Hg, 95% CI -2.57 to -0.48); high-quality to moderate-quality evidence that diet-only interventions improve DBP (MD -2.05 mm Hg, 95% CI -2.93 to -1.16) and blood lipids (triglycerides (MD -0.10 mmol/L, 95% CI -0.14 to -0.06) and LDLc (MD -0.19 mmol/L, 95% CI -0.32 to -0.06)); and moderate-quality evidence that physical activity-only interventions improve SBP (MD -9.7 mm Hg, 95% CI -11.05 to -8.35), DBP (MD -7.29 mm Hg, 95% CI -8.42 to -6.16) and HDLc (MD 0.08 mmol/L, 95% CI 0.04 to 0.11) compared with usual care.ConclusionsLifestyle interventions improve blood pressure and blood lipid profiles in adult South Asians at risk of CVD. Tailored interventions should be used to modify cardiovascular risk factors in this at-risk group.Prospero registration numberCRD42018090419.
Project description:Aims/hypothesisGestational diabetes mellitus (GDM) is associated with an increased future risk of obesity in the offspring. Increased adiposity has been observed in the newborns of women with GDM. Our aim was to examine early fetal adiposity in women with GDM.MethodsObstetric and sonographic data was collated for 153 women with GDM and 178 controls from a single centre in Chennai, India. Fetal head circumference (HC), abdominal circumference (AC), femur length (FL) and biparietal diameter (BPD) were recorded at 11, 20 and 32 weeks. Anterior abdominal wall thickness (AAWT) as a marker of abdominal adiposity at 20 and 32 weeks was compared between groups. Adjustments were made for maternal age, BMI, parity, gestational weight gain, fetal sex and gestational age.ResultsFetuses of women with GDM had significantly higher AAWT at 20 weeks (β 0.26 [95% CI 0.15, 0.37] mm, p < 0.0001) despite lower measures of HC, FL, BPD and AC. AAWT remained higher in the fetuses of women with GDM at 32 weeks (β 0.48 [0.30, 0.65] mm, p < 0.0001) despite similar measures for HC, FL, BPD and AC between groups. Both groups had similar birthweights at term. There was an independent relationship between fasting plasma glucose levels and AAWT after adjustment as described above.Conclusions/interpretationA 'thin but fat' phenotype signifying a disproportionate increase in adiposity despite smaller or similar lean body mass was observed in the fetuses of mothers with GDM, even at 20 weeks, thus pre-dating the biochemical diagnosis of GDM. Increased AAWT may serve as an early marker of GDM.
Project description:South Asians (SAs), people from the Indian subcontinent (e.g., India, Pakistan, Bangladesh, Sri Lanka, and Nepal) have a higher prevalence of cardiovascular disease (CVD) and suffer from a greater risk of CVD-associated mortality compared to other global populations. These problems are compounded by the alterations in lifestyles due to urbanization and changing cultural, social, economic, and political environments. Current methods of CV risk prediction are based on white populations that under-estimate the CVD risk in SAs. Prospective studies are required to obtain actual CVD morbidity/mortality rates so that comparisons between predicted CVD risk can be made with actual events. Overwhelming data support a strong influence of genetic factors. Genome-Wide Association Studies (GWAS) serve as a starting point for future genetic and functional studies since the mechanisms of action by which these associated loci influence CVD is still unclear. It is difficult to predict the potential implication of these findings in clinical settings. This review provides a systematic assessment of the risk factors, genetics, and environmental causes of CV health disparity in SAs, and highlights progress made in clinical and genomics discoveries in the rapidly evolving field, which has the potential to show clinical relevance in the near future.
Project description:Objective:The purpose of this study was to develop and test the feasibility of a culturally tailored Diabetes Prevention Programme (DPP) for US South Asians, a large population with high diabetes risk. Design:The South Asian Health and Prevention Education (SHAPE) study included: (1) focus group discussions with South Asian adults to understand views of lifestyle behaviours and diabetes prevention; (2) modification of the US DPP for South Asians and (3) a pilot, pre-post study to test the feasibility and impact of delivering the culturally tailored programme. Setting:The study was conducted in Atlanta, Georgia, USA. Focus group discussions and intervention classes were held at locations within the community (eg, South Asian restaurants, a public library, university classrooms, a South Asian owned physical therapy studio). Participants:The focus group discussions (n=17 with 109 individuals) included adults aged 25 years of older who self-identified as South Asian. Groups were stratified by age (25-40 years or older than 40 years) and sex. The SHAPE pilot study included 17 (76.5% male with a mean age of 46.9±12 years) South Asian adults aged 25 years or older with pre-diabetes and body mass index (BMI) >22 kg/m2. Results:Formative data from 17 focus group discussions and a community board guided the modification of the DPP curriculum to reflect cultural food preferences and include tools to leverage social support, create a stronger foundation in exercise and overcome culturally specific barriers. The SHAPE pilot study included 17 South Asian adults with pre-diabetes and BMI >22 kg/m2. There were positive changes in participants' weight, waist circumference, blood pressure, plasma lipids, HbA1c and other cardiometabolic markers postintervention and 55% of participants regressed to normoglycaemia. Conclusion:These results provide important information on the barriers faced by US South Asians in participating in 'standard' lifestyle change programs, indicate the feasibility of culturally tailored programmes and show positive impact of a culturally tailored programme for diabetes prevention in the South Asian population.
Project description:ObjectiveTo evaluate the association between risk perception and attendance in a diabetes prevention programme among South Asians with a high risk for diabetes.DesignAn observational study. We measured risk perception during the baseline interview with causal beliefs, perceived susceptibility and perceived controllability. We used logistic regression to examine the relationship between risk perception and attendance. We adjusted for relevant sociodemographic factors, screening results and psychosocial factors.SettingThe Hague, the Netherlands.SubjectsFive hundred and thirty-five Hindustani Surinamese (South Asians) aged 18-60 years from a lifestyle-versus-control intervention for the prevention of diabetes.ResultsIn total, 68·2% attended the lifestyle or control intervention. Participants perceived lifestyle and heredity to increase the risk of diabetes and perceived increasing physical activity to decrease it. Only 44·2% of the participants perceived themselves as susceptible to diabetes and only those who perceived a family history of diabetes as a cause of diabetes appeared to be more inclined to attend. However, after adjustment for confounding, the association was not statistically significant.ConclusionsRisk perception was not significantly associated with attendance. The results suggest that increasing the risk perception alone in this South Asian population is unlikely to increase the attendance at a diabetes prevention programme.
Project description:BackgroundObservational studies have shown that alcohol consumption above the recommended limit is associated with increased cardiovascular disease (CVD), although its association in South Asians is unclear. Less is known regarding the association between alcohol consumption and cardiovascular health (CVH), assessed by the American Heart Association's Life's Simple 7 (LS7) health metrics among those with South Asian ancestry.MethodsThis analysis included 701 participants without CVD from the Mediators of Atherosclerosis in South Asians Living in America (MASALA) cohort (2015 to 2018). Based on a personal history questionnaire, participants were divided into never, former, and current drinkers. The current drinking category was further classified into 1 to 3 drinks/wk, 4 to 7 drinks/wk, and >7 drinks/wk. The consumption of 5 or more drinks on 1 occasion in the past month was defined as binge drinking. Each LS7 component was given a point score of 0, 1, or 2. The total score was categorized into 0 to 6, 7 to 10, and 11 to 14 to represent poor, intermediate, and ideal CVH, respectively. We use multinomial logistic regression to examine the association between alcohol consumption and CVH.ResultsIn the MASALA cohort (mean age = 59 years, 43% female), participants consuming >7 drinks/wk had the lowest mean CVH score. Compared with never drinkers, male participants consuming >7 drinks/wk were less likely to have intermediate CVH (0.44 [0.08, 0.91]) and ideal CVH (0.23 [0.03, 0.96]). Binge drinking was associated with significantly lower odds of ideal CVH compared with never drinkers.ConclusionWe found evidence of an inverse association of moderate to heavy alcohol consumption and ideal CVH in South Asian men. These findings further underscore the important relationship between alcohol consumption and CVH in this unique population of South Asians.
Project description:AimWe investigated the association between acculturation strategies and cardiometabolic risk among South Asian (SA) immigrants in the US.MethodsIn this cross-sectional analysis of data from 849 SA participants in the Mediators of Atherosclerosis in SAs Living in America (MASALA), we performed multidimensional measures of acculturation to categorize the participants into three acculturation classes: separation (preference for SA culture), assimilation (preference for US culture), and integration (similar preference for both cultures). Differences in glycemic indices, blood pressure, lipid parameters and body composition by acculturation strategy were examined.ResultsWomen in the integration class had the lowest prevalence of diabetes (16.4%), prediabetes (29.7%), fasting and 2-h glucose compared to women in the separation class with the highest prevalence of diabetes (29.3%), prediabetes (31.5%), fasting and 2-h glucose and 2-hr insulin (all p < 0.05). Women in the assimilation class had significantly lower triglycerides, BMI, and waist circumference and higher HDL compared to women in the separation class after adjusting for age, study site, and years in the US. After additionally accounting for socioeconomic/lifestyle factors, women in the assimilation class had significantly lower triglyceride and higher HDL levels compared to women in the separation class (p < 0.01). There was no significant association between acculturation strategies and cardiometabolic risk in SA men.ConclusionSA women who employed an assimilation or integration strategy had a more favorable cardiometabolic profile compared to women using a separation strategy. Future research should investigate the behavioral and psychosocial pathways linking acculturation strategies with cardiometabolic health to inform preventive interventions among SAs living in America.